Frictional mechanism and expander therefor



Jan. 79 1947. F. VAN ARSDELL FRICTIONAL MECHANISM AND EXPANDER THEREFOR Filed Oct. 2, 1944 i A n rfw` E ceive retractor springs stented Jan. 7, 1947 I rmc'rroNAL MECHANSM AND EXPANDER TEEBEFOB tol The B. F.

Fred van Arsdell, Cuyahoga Falls,

Goodrich Company, N. Y., a corporation of New York Ohio, assignor y New Yorlr,

Application October 2, 1944, Serial No. 556,806

6 Claims. (CLIM-152) This invention relates to frictional mechanism and especially to expanders for expander-operated brakes, and is especially useful in the construction of brakes for aircraft, although features of the invention are useful also in other frictionally-operable structures, such as clutches and brakes for other purposes.

Objects of the invention areto provide a multi- I stage expander capable of a high degree of lift movement, to provide effective strength and high lift without destructive hinging action, to provide an outwardly expansible brake expander with s. plurality of independently inatable chambers, to provide for independently operating chambers of a multiple chamber cxpanderfrom opposite ends thereof.

These and other objects will appear from the following description andy the` aoco panying drawing.

Of the drawing,

Fig. 1 is a side view of a brake partially broken away and partly vin section having an expander constructed in accordance with and embodying the invention.

Fig. 2 is a cross-section thereof taken on line 2-2 of Fig. 1.

Referring to the drawing. the numeral II! designates a rotatable brake drum andthe numeral II a torque member for supporting a brake structure for cooperation therewith. The torque member has a fixed odset flange at its periphers1 and a removable offset flange I4 is secured thereto, as by bolts I5 to provide an outwardly-facing channel I6; Seated in the channel is an expander I1. Upon the face of the expander is a series of brake shoes I8 in position to engage the brake drum The shoes are grooved at their meeting margins, as at I3 to re- 20. The ends of the springs may engage the flanges I3, I4 as for example in the manner shown in the Hunter Pat-g ent 2,174,724, and the springs are bowed inwardly to press the brake shoes toward the expander. The brake shoes are of heat-resisting friction material such as brake lining composition. y

The expander, which is preferably of rubber or other rubber-like materialjis substantially rectangular in cross section so as to illl the channel space beneath the shoes and is preferably of discontinuous arcua A pair of superimposed expansion passages or chambers formed in the expander and these extend substantially throughout extends laterally across the expander with the inner and outer walls of the chamber substantially in contact in the panded position of the expander, the margins 21, 28 of the chamber being preferably turned outwardly in a radial direction and being more open to avoid ination.

ing action during Hinging action at spective layers the margins is rendered less severe also by forming theradially outer chamber of lesser width than the radially inner chamber so that ilexure at the margins of the respective chambers can be effected with a minimum of interference of one with the other.

To provide strength to resist high pressure while nevertheless facilitating the .radially outward expansion, each chamber is surrounded by reinforcing material which may be re- 30, 3|, 32 and 33, 34, 35 of thin fabric having equal strength in two bias laid so that its warp and filler the expander. fabric are embedded in and are united to the rubber-like material of the body by the molding vand vulcanizing operation in forming the expander. r

The expander extends about the channel I6 with its closed ends 40, 4I in close proximity. Near the ends of the expander, metallic pipe connections 42, 43 are provided and the channel is formed with apertures surrounded by depressions 44, 45 for clearing the connections. 'Each' connection has an enlarged head, such as 46 adapted tobe received vin the expander chamber, and is threaded, as at 41, to receive a nut 48 adapted to clamp a washer 49 against the wall of the expander. 'I 'he arrangement is such that the expander wall is clamped between the head the washer-49 to seal the opening. A second nut 50 engages the same thread and clamps the expander to the channel. Connection 42 communicates with chamber 26 which at end 40 of the expander extends beyond chamber 25, and connection 43 communicates with chamber 26 at the opposite end 4I of the expander. Each metallic connection may be of L shape, as shown, and connection thereto may be made from a source of fluid pressure by a swivel connection 60. A bleeder 6I may be provided to remove air from the system. The fluid connections at opposite ends of the expander serve the purpose of anchoring the ends of the expander while also preventing congestion of space by distributing the connections at different positions along the channel.

The construction of the expander is such that it may be built in straight form and then be vulcanized in arcuate form if desired or in flat form and then wound about the channel.

The arrangement of a plurality of expander bursting under vchambers in superimposed relation permits operation of a sin e expander from'two pressurefluid systems and, if desired, at different fluid pressures.

For example, one chamber may be operated by fluid pressure from a service brake and the other chamber may be operated from an emergency brake. In another use of the fluid system the chamber 2B maybe connected to a source of comprising a body 3 iiuid pressur for braking purposes while the chamber 25 may be connected to the same source of pressure or a different source controlled by a shut-olf valve and used for adjusting the nonbraking position of the shoes. Such an arrangement is of advantage in keeping the amount 'of lift of the shoes low regardless of their condition due to'wear and is of especial advantage where the brake is to be operated by a foot-actuatedpressure cylinder as on light planes not equipped with powerful hydraulic pressure systems. In a further alternative manner of' use, both chambers may be simultaneously inated for obtaining a high degree of lift of the brake shoes and then simultaneously deflated, this being advantageous, for example, in cases where close clearances are not desired in the retracted condition of the brake.

Variations may be made without departing from the scope of the invention as it is defined by the following claims.

I claim: 4

1. An expander for a frictional mechanism comprising a body oi' rubber-like material having circumferentially extending radially inner and outer faces and having radially superimposed chambers in said body between said faces thereof, means for conducting activating fluid to said chambers, exible reinforcing material in said body extending about one of said chambers only, and additional flexible reinforcing material in said body extending about the other only of said chambers, the individual reinforcements providing substantial independency of restraining action of the'reinforcements under individual expansion of the chambers.

2. An expander for a frictional mechanism of rubber-like material having circumfientially extending radiallyV inner and outer fa'es and having radially superimposed chambers in said body between said faces thereof, the radially inner of said chambers being relatively of greater width than the radially outer of said chambers with the margins of the inner chamber extending laterally beyond the body extending only, and addisaid body ible reinforcing about the wider inner chamber tional flexible reinforcing material in extending about the narrower outer chamber only, the individual reinforcements providing substantial independency of restraining action of the reinforcements under individual expansion of the chambers.

3. An expander for comprising an annular body of rubber-like material having a pair of ends, said body having circumferentially extending radially inner and outer faces and having radially superimposed chambers in said body between said faces thereof and terminating adjacent the ends of said body, means at an end of said body for conducting actuating uid to one of said chambers, means at the other end of said body for conducting actuating fluid to the other of said chambers. exible reinforcing material in said body extending about one of said chambers only, and additional exa frictional mechanism-v 4 4. In a frictional mechanism having relatively rotatable radially'nested members and a friction element 'carried by the radially inner oi said members, an expander radially within said uid to said chambers, exible reinforcing material in said body extending about one of said chambers only, an additional exlble reinforcing material in 6. In a frictional mechanism having relatively rotatable radially nested members and a frictional element carried by the radially inner of said members, an expander radially within said element for moving said element into engagesaid body extending about the other only of said FRED VAN 

